• Neurosurgery
  Teaching Files
• Home
• How to take a History
• Angiograms
• Spinal Levels
• Rostrocaudal Deterioration
• Neurological Emergencies
• Third Ventriculostomy
• Pituitary Tumors
• Anatomy & Imaging
• Clinical Presentation Syndromes
• Prolactinoma
• Cushing's Disease (ACTH Tumors)
• Nonsecreting Tumors
• Gamma Knife
• Neurosurgery at Upstate

Pituitary Tutorial—Nonsecreting Tumors

AKA null-cell tumors, old name was "chromophobe andenomas."

Nonsecreting pituitary tumors are one of the most common of the known pituitary tumors. And, well, "nonsecreting" is a bit of a misnomer. A lot of these tumors DO secrete stuff like alpha-subuit, but it has no known hormonal function and has been difficult to assay for in the past.

We will discuss:

• History and physical examination
• Laboratory and imaging tests which help in diagnosis
• Differential diagnosis of nonsecreting tumors
• Treatmentof this tumor
• We will also mention some controversies in the treatment of nonsecreting pituitary tumors

History and Physical Examination

Nonsecreting tumors typically present with two syndromes:

1. Syndrome of mass effect
   • Visual disturbances (unilateral or bilateral visual loss, bitemporal hemianopia)
   • Diplopia (from lateral pressure on cranial nerves in the cavernous sinus
   • Headache
   • Isolated or pan-hypopituitarism (male or female sex hormones, thyroid, cortisol)
2. Incidentally discovered nonsecreting tumors ("let's get an MR to work up this headache...")

Laboratory and imaging studies

Laboratory studies of use include a prolactin level, which is often elevated in these patients. (Why?) So the question then arises whether this is a prolactinoma or a nonsecreting tumor. How to sort this out? Well, no one can tell you for sure, but it is hard to get your prolactin over 150 except with a prolactinoma. Also, you should get around 100 of prolactin for each cm of tumor diameter: a ratio of prolactin/tumor diameter significantly less that this makes one worry about a nonsecreting tumor.

Imaging studies best performed is the MR with and without gadolinium enhancement. Really, folks, the days of the CT scan for diagnosing pituitary tumors are over. MR scanning, which drops bone out of the image, shows the tumor and its surrounding structures with exquisite detail. Small tumors are best appreciated on MR. You don't even catch any X-rays, they do it with magnets (really).

Differential diagnosis of nonsecreting pituitary tumors

Unless clearly expanding the sella and pushing out from here, these tumors can mimic/be mimiced by suprasellar lesions such as:

• Other tumors: meningioma, craniopharyngioma, germinoma, hamartomas, hypothalamic gliomas, PNETS, etc.
• Rathke's cleft cysts
• Aneurysms (MR should help a lot here)
• Arachnoid cysts (MR should help a lot here too)

Prolactin levels for all of these problems rarely exceed 150 ng/ml. Also, there is a (very) rough correlation between pituitary tumor size and expected prolactin level: a 10 mm tumor should produce a serum prolactin of around 100 ng/ml. This rule becomes useful when you have, e.g., a 30 mm tumor and a prolactin level of 50 ng/ml: think of a nonsecreting tumor here, not prolactinoma.

Treatment of nonsecreting tumors

The mainstay of treatment for nonsecreting tumors is surgical debulking followed by either close observation or RT.

Controversies in nonsecreting tumors

Among the controversies in the treatment of nonsecreting tumors are:

• Should incidentally discovered nonsecreting tumors be operated or watched?
• After surgery for these tumors, should RT be done? Ever?
• Should tumors with marginal prolactin/diameter ratios be tried on dopamine agonists for a time? What if the prolactin decreases?

Such questions provide grist for controversies during endocrinological and neurosurgical meetings.